Axial swirl device for a contact and separation member

ABSTRACT

An axial swirl device for a contact and separation member for mass-exchangend separation apparatuses, having a sleeve (1) which has a closed inlet end and an open outlet end and vanes (2) located on the outer surface of the sleeve to extend at an angle with respect to the longitudinal axis of the sleeve (1) in the zone of its outlet end. A deflector means (6) is provided at the outlet end of the sleeve (1) coaxially therewith. The deflector means (6) is mounted coaxially with the sleeve (1) at the outlet end thereof and made in the form of a body of revolution having the generant of its outer surface which is so shaped that a tangent line drawn to the generant at the point thereof remotest from the vanes (2) extends at an angle of from 0° to 15° with respect to the longitudinal axis of the sleeve (1).

TECHNICAL FIELD

The invention relates to the gas-liquid technology, and in particular,it deals with mass-exchange and separation apparatuses for gas-liquidsystems, and more specifically, the invention relates to axial swirldevices for contact and separation members.

The invention may be used in apparatuses employed in the gas, chemical,oil, thermal power and other industries for providing equipment forcarrying out mass-exchange processes in gas-liquid systems (absorption,desorption and rectification and also in processes of mechanicalscrubbing).

The invention may be most effectively used in gasliquid mass-exchangetowers and high-pressure separators in which heat- and mass-exchangeprocesses occur with subsequent separation of contacted phases:separation of gas condensate, drops of contacted absorbent or refluxfrom a vapour and gas carrier flow, mineralized formation water andinhibitors of hydrate formation (glycols or methanol) from a gas flow inplants for the preparation and processing of natural hydrocarbon gasesand petroleum gases.

BACKGROUND OF THE INVENTION

There is a problem nowadays in the way of improving efficiency, loweringmetal weight and improving reliability and output of mass-exchangetowers and gas-liquid separators.

As mass-exchange towers and gas-liquid separators are basic apparatusesused in processes of preparation and processing of gas, bringing asolution to this problem would open the way to providing compact gasprocessing and separation plants for gas condensate continental shelfdeposits and polar regions where low weight, small size and highcapacity-to-mass ratio equipment is especially appreciated.

Known in the art is a multiple-vane axial swirl device for separatingphases, comprising a coaxial pipe extending through a bunch of solidinclined vanes for gas recirculation in a circuit "deposition zone -reduced pressure zone" in the central area of the tail part of the swirldevice (cg. USSR Inventor's Certificate No. 436677, Int.Cl. B 04 C 3/06,publ 25.07.1974).

This swirl device has a large axial size because of an unwieldyrecirculation system.

Also known in the art is an axial swirl device for a contact andseparation member having vanes with through radial passages (cf. USSRInventor's Certificate No. 203622, Int.Cl. B 01 d, publ. 9.10.1967). Adeflector in the form of a converging tube is provided above, andadjacent to the swirl device for restricting the swirled gas and liquidflow passing therethrough.

This construction allows processes of heat- and mass-exchange and phaseseparation in gas-liquid systems to be intensified.

However, the converging tube restriction of swirled flow results inincreased energy consumption for forcing the flow through while loweringthroughput capacity since flow velocity at the outlet edge of theconverging tube is limited to a certain value so as to comply withconditions for ensuring reliable separation of contacted gas and liquidphases.

Known in the art is an axial swirl device for centrifugal separation ofphases of a gas and liquid mixture (cf. U.S. Pat. No. 3,693,229, Int.Cl.B 01 d 45/12). The swirl device comprises a bunch of inclined vanessecured to a central sleeve, and for recirculation of gas beingseparated, use is made of a reduced pressure zone created axially alongthe sleeve of the swirl device, the gas being sucked into the sleevethrough passages of individual vanes (hollow vanes). The vane passagesmay, in certain applications, extend tangentially to the interior of thecentral sleeve. The sleeve proper has a cigar-like extension downstreamthe outlet edge of the vanes, with a gradual narrowing of its outersurface through a decrease in the wall thickness to fit the dimensionsof the open cylindrical cavity.

This construction of the axial swirl device makes it possible toincrease throughput capacity of a contact and separation member in termsof gas as compared with the abovedescribed swirl devices.

However, throughput capacity in terms of liquid remains low in thisprior art device because of a weak swirling of liquid drops that breakthrough together with recirculated gas. This weak swirling calls for aconsiderable distance at which the tail cigar-like portion of the swirldevice should be spaced from a separation unit so as to remove theseparated liquid film.

In addition, the cigar-like extension of the sleeve of the swirl deviceenables individual drops passing along its surface to separate at asmall distance from the central axis of the swirl device where swirlingof the flow is rather ineffectual for reliable separation of phases withsubstantial liquid flow rates.

Liquid may be accumulate in the interior of the sleeve when the priorart apparatus operation is suspended so that additional amounts ofheating steam and hot water are required for removing the liquid duringinspection and repairs of the apparatus.

The abovementioned disadvantages of the prior art swirl device impose apreferably horizontal working position, thus restricting the field ofapplication since vertical position of a swirl device is generallydesirable in mass-exchange apparatuses.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an axial swirl device forcontact and separation members for massexchange and separationapparatuses, wherein, owing to a new structural arrangement of the flowduct, high efficiency of heat- and mass-exchange processes and phaseseparation is ensured with a reduced axial size of the device.

The invention essentially resides in that an axial swirl device for acontact and separation member for mass-exchange and separationapparatuses, comprising a hollow sleeve having a closed inlet end and anopen outlet end on the sides of inlet and outlet of fluid being swirled,respectively, and vanes extending on the outer wall of the sleeve at anangle with respect to the longitudinal axis of the sleeve in the zone ofthe outlet end thereof, wherein, according to the invention, the deviceis provided with a deflector means mounted coaxially with the sleeve atthe outlet end thereof and comprising a body of revolution having agenerant of the outer surface thereof which is so shaped that a tangentline drawn to this generant at the point thereof remotest from the vanesextends at an angle of from 0° to 15° with respect to the longitudinalaxis of the sleeve.

This structural arrangement of the deflector means makes it possible tointensify heat- and mass-exchange processes between liquid and gas,first owing to wetting of the surface of the deflector means; second,owing to the tangential direction of drops incident upon its surface;and third, owing to an extension of the active turbulent zone of contactbetween gas and liquid by the provision of the deflector means. Inaddition, the deflector means allows the total length of the separationzone to be substantially reduced. This is achieved due to the fact thatdrops separated from the edge of the deflector means are subjected to astronger action on the part of centrifugal forces as compared to whatoccurs in prior art swirl devices owing to a greater distance at whichthe edge of the deflector means is spaced from the longitudinal axis ofthe swirl device.

The deflector means is preferably made in the form of a diffuser havingits narrow and secured to the sleeve and the flare end of an outsidediameter (D₁) equal to 0.5-0.7 of the diameter of the circumscribedcircle of the vanes (D).

The provision of the deflector means in the form of a diffuser makes itpossible to make the swirled jet more stable without appreciableincrease in drag by choosing the diameter D₁ so as to correspond to theboundary of the central vertical core of the swirled jet. This can beexplained as follows. A simplified model of a swirled gas flow is ahollow rotating jet with kinematically and dynamically weak core. If theflare end of a diffuser is equal to the diameter of the central vortex,i.e. if it does not restrict the swirled jet thus formed, there is noappreciable increase in drag. The following useful technical results arethus obtained: a swirled jet is formed which is not liable to damping;processes of heat- and mass-exchange and phase separation in agas-liquid system are intensified.

Through radial ports preferably made in the sleeve wall which arecircumferentially spaced so as to form at least one row of ports.

This structural arrangement of the axial swirl device makes it possibleto put in order the removal of liquid entrained with a backward vorticalflow or with a recirculation gas flow from the interior of the sleevethereby preventing liquid from accumulating in the sleeve. In addition,the through radial ports may extend through the body of the vanes so asto define recirculation passages for gas.

The end of the deflector means adjacent to the sleeve may have theinside diameter which is smaller than the inside diameter of the sleeveso as to form a shoulder on the inner surface of the sleeve.

This construction of the axial swirl device allows for a more reliableremoval of liquid from the interior of the sleeve, thus preventingentrainment of liquid along the axis of the swirl device.

The radial ports of the swirl device are preferably made between thevanes.

This construction of the swirl device ensures removal of liquid forsprinkling gas-liquid flow moving through the inlined passages thuscontributing to a hydrodynamic coagulation of small-size drops, andhence, to a more complete separation of drops from the swirled gas flow.

The radial ports may be made in the outlet end of the sleeve, downstreamthe outlet ends of the swirl device vanes.

This construction makes it possible to ensure a more intensive removalof liquid through the ports owing to suction thereof by the flow leavingthe vanes.

The length of the deflector means is preferably equal to 0.2-1.0diameter of the circumscribed circle of the swirl device vanes.

This construction ensures the most optimum operation of the swirldevice. Changing from small to larger diameter of the swirl device, thisratio generally decreases from 1.0 to 0.2 depending on specificapplication.

Finally, a streamline member is preferably provided at the inlet end ofthe sleeve coaxially therewith, a through opening being made in thestreamline member wall which is inclined at an acute angle with respectto the sleeve axis and located in the zone of intersection of the innersurface of the streamline member with the sleeve axis.

This construction of the streamline member lowers the admissionhydraulic losses, contributes to blowing a spurious vortex off at theaxis of the swirl device and also ensures removal and drainage of liquidupon suspension of operation of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail with reference toaccompanying drawings illustrating specific embodiments of theinvention, in which:

FIG. 1 is a schematic view of an axial swirl device according to theinvention, in longitudinal section, with a deflector means in the formof a cone having a straight line generant;

FIG. 2 shows a partial developed view of an axial swirl device in whichhollow vanes alternate with solid vanes;

FIG. 3 is an embodiment of a deflector means in the form of acylindrical extension of a swirl device sleeve with a shoulder on theinner side thereof and with all vanes of the swirl device being sold;

FIG. 4 is an embodiment of a deflector means having a curved linegenerant, with a streamline member having an opening and with all vanesof the swirl device being solid.

BEST MODE FOR CARRYING OUT THE INVENTION

An axial swirl device has a central hollow sleeve 1 (FIG. 1) to whichare secured inclined vanes 2 and certain among them may have a passage 3terminating in the interior 4 and extending in the direction towards thelongitudinal axis or tangentially with respect to the surface of theinner wall 5. A deflector means 6 is mounted coaxially with the centralsleeve 1 with its outlet edge 7 facing towards the outlet of swirledfluid, the end of the deflector means 8 being secured to the sleeve 1.The deflector means 6 has the outer surface 9 in the form of a body ofrevolution with a generant in the form of either straight line or asmooth curved line of a shape such that a tangent line to the outersurface of the means 6 at the edge 7 should extend at an angle α of from0° to 15°.

FIG. 2 shows a partial developed view of an embodiment of the axialswirl device in which the hollow vanes 2 having the passages 3 alternatewith solid vanes 2'. It should be noted that both configurations of thevanes, their number and position may vary.

With reference now to FIG. 3, it shows an embodiment of the deflectormeans 6 in the form of a cylindrical extension of the sleeve 1 of theswirl device. The end 8 of the deflector member 6 is smaller than theinside diameter of the sleeve 1 and defines a shoulder 10, and at leastone row of through radial ports 11 are provided under the shoulder, theports terminating in the intervane zone of the swirl device. A tangentline drawn to the outer surface of the deflector member 6, at the edge 7thereof, extends in parallel with the longitudinal axis of the sleeve,the angle α=0°, and the diameter D₁ is equal to the sleeve diameter.

FIG. 4 shows an embodiment of the deflector means 6 having the generant9 of the outer surface in the form of a curved line, the sleeve 1 havinga streamline member 12 secured to the sleeve 1 and having a throughopening 13 inlined at an acute angle β with respect to the sleeve axis,the opening being located in the zone of intersection of the innersurface 14 of the streamline member with the axis of the sleeve 1. Theports 11 are located downstream the outlet ends 15 of the vanes 2.Curvature and configuration of the generant are chosen to comply withthe condition D₁ =(0.5-0.7) D, α not exceeding 15° and the heightH=(0.2-1.0)D.

FIGS. 1 through 4 show the vertical modification of the swirl device,but it is understood that it can work in horizontal or inclined positionas well.

The axial swirl device functions in the following manner.

A flow of liquid drops is directed together with gas towards the swirldevice as shown by arrows in the drawings. When the flow passes throughthe swirl device, it is swirled about the longitudinal axis of thecentral sleeve 1 and continues to move further in a vortical chamber 16(the wall of the vortical chamber in FIG. 1 is shown with two dottedlines as an extension of the outer circumscribed surface of the vanes)in the form of a swirled jet. Heat- and mass-exchange processes thusoccur between liquid and gas.

A reduced pressure zone is formed in the direction along thelongitudinal axis of the swirl device. Gas, which is removed from theseparation zone flows naturally together with the entrained liquid dropsfor recirculation through the passages 3 into the interior 4 whereinpressure is at the minimum and leaves, in the form of a rotating jet,through the end 8 of the deflector means 6. In the simplest case, liquiddrops are thrown against the inner wall 5 of the sleeve 1 and then dripdown along the deflector 6 towards the edge 7 wherefrom they arestripped off by the swirled jet of fluid along a conical trajectory asshown by inclined dotted lines in FIG. 1.

The outer surface 9 of the deflector 6 is wetted with liquid sinceliquid drops flying out of the intervane space would slide over thesurface 9 thus contributing to intensification of heat- andmass-exchange processes in a gas-liquid system.

For a more reliable separation of drops entrained with the recirculationflow, there are provided the ports 11 (FIG. 3) disposed downstream theshoulder 10. The provision of the ports in the intervane zone results ina less intensive removal of liquid than in the case where the ports aredisposed downstream the outlet ends 15 of the vanes 2 (FIG. 4).

The streamline member 12 lowers inlet hydraulic losses, but liquid wouldaccumulate on the inner surface 14 thereof. The inclined through opening13 is provided for blowing the liquid off towards the center of thevortex. Liquid residues are drained through this opening when operationof the apparatus is suspended.

The axial swirl device according to the invention makes it possible tosolve the problem of providing a smallsize contact and separation memberfor heat- and mass-exchange towers and gas-liquid separators.

INDUSTRIAL APPLICABILITY

The invention allows an axial swirl device to be provided forhigh-capacity contact and separation members for a large variety ofmass-exchange and gas-liquid separators. It may be used in the oil andgas and chemical industries and in thermal power engineering for a widerange of processes where gas-liquid systems should be handled.

I claim:
 1. An axial swirl device for a contact and separation memberfor mass-exchange and separation apparatuses, comprising:a hollow sleevehaving a closed inlet end and an open outlet end respectively on aninlet side and an outlet side of fluid being swirled, vanes located onan outer surface of the sleeve and extending at an angle with respect tothe longitudinal axis of the sleeve at the outlet end of said hollowsleeve, a deflector means provided on said hollow sleeve and mountedcoaxially with the sleeve at the outlet end thereof and made in the formof a body of revolution having a generant of an outer surface thereofwhich is so shaped that a tangent line drawn to this surface at thepoint most remote from the vanes extends at an angle of from 0° to 15°with respect to the longitudinal axis of the sleeve, the end of thedeflector means secured to the sleeve having an inside diameter which issmaller than the inside diameter of the sleeve so as to define ashoulder at the inner surface thereof, the length of the deflector meansbeing equal to 0.2-1.0 times the diameter of a circumscribed circle ofthe vanes, and a streamline member provided at the inlet end of thesleeve coaxially therewith, a through opening being provided in thestreamline member wall to extend at an acute angle with respect to thesleeve axis, the through opening being located in the zone ofintersection of the inner surface of the streamline member with thesleeve axis.
 2. An axial swirl device for a contact and separationmember for mass-exchange and separation apparatuses comprising:a hollowsleeve, one end of said sleeve being closed and disposed on an inletside of fluid being swirled, the other end of said sleeve being open anddisposed opposite to the closed end on an outlet side of fluid beingswirled; vanes located on the outer surface of said sleeve, extending atan angle with respect to the longitudinal axis thereof in proximity tosaid open end of said sleeve, a swirl chamber defined by a continuationof the circumscribed outer surface of said vanes; a deflector meansmounted inside said swirl chamber in coaxial relation to said sleeve atthe open end thereof and made in the form of a body of revolution whichis a continuation of the outer surface of said sleeve and which is soshaped that a tangent line to a generant of an outer surface of saidbody of revolution at the point most remote from said vanes is tiltedtoward the inner wall of the swirl chamber at an angle of up to 15° withrespect to the longitudinal axis of said sleeve, the deflector meanscomprising a diffuser having a narrow end secured to the sleeve, thevanes having a circumscribed circle and a flared end having an outsidediameter equal to 0.5 to 0.7 times the diameter of the circumscribedcircle of the vanes.
 3. An axial swirl device according to claim 2, inwhich through radial ports are circumferentially made in the wall of thesleeve such that they form at least one row of ports.
 4. An axial swirldevice according to claim 3, in which the radial ports are locatedbetween the vanes.
 5. An axial swirl device according to claim 3, inwhich the radial ports are made at an end of the sleeve downstreamoutlet ends of the vanes.
 6. An axial swirl device for a contact andseparation member for mass-exchange and separation apparatusescomprising:a hollow sleeve, one end of said sleeve being closed anddisposed on an inlet side of fluid being swirled, the other end of saidsleeve being open and disposed opposite to the closed end on an outletside of fluid being swirled; vanes located on the outer surface of saidsleeve, extending at an angle with respect to the longitudinal axisthereof in proximity to said open end of said sleeve, a swirl chamberdefined by a continuation of the circumscribed outer surface of saidvanes; a deflector means mounted inside said swirl chamber in coaxialrelation to said sleeve at the open end thereof and made in the form ofa body of revolution which is a continuation of the outer surface ofsaid sleeve and which is so shaped that a tangent line to a generant ofan outer surface of said body of revolution at the point most remotefrom said vanes is tilted toward the inner wall of the swirl chamber atan angle up to 15° with respect to the longitudinal axis of said sleeve,the vanes having a circumscribed circle and the length of the deflectormeans being equal to 0.2 to 1.0 times the diameter of the circumscribedcircle of the vanes and in which a streamline member is provided at theend of the sleeve in coaxial relation thereto, a through opening beingprovided in a wall of said streamline member to extend at an acute angleto the sleeve axis, the opening being located in a zone of intersectionof the inner surface of the streamline member with the sleeve axis.